A spamzombie has YOUR email address in its database. When it blasts its spam, it randomly picks one of the many in its list to put into the "FROM" field of the spam it sends to everyone. Sometimes it's YOUR address. So when it spams to a greylisting server, it bounces the "try later" back to the sender, in the FROM field... to you.
This explanation makes sense
except the original post said the bounces were from organizations that he knew and may have subscribed to at one time. Would a spambot target in this manner? Too coincidental? If Benheim had no association with the organizations in the bounced messages, that to me would make more sense.
